High molecular weight B-cell growth factor augmentation substance continues to elude all efforts at isolation and characterization. Using linked-scan and FAB mass spectrometry, a series of oligosaccharides of interest in demyelinating diseases have been sequenced. The heat stable factor necessary for the steroid binding complex of the adrenocortical pregnenolone binding protein has been identified as adenosine 3',5'- diphosphate. A wide variety of peptides have been analyzed by linked- scan and FAB mass spectrometry